The book is a study of the shooting of suspected civilian informers by the Cork city IRA in 1920-1921. During a one-year period, at least twenty-four Cork civilians died at the hands of the IRA, including a two-week span that saw eight civilians shot. IRA sources claim some of the civilians were members of an Anti-Sinn Fein Society, a pro-British intelligence network operating in the city. The book analyses the existence of such a network, alleged IRA persecution of ex-soldiers, and the strength of the IRA intelligence efforts in Cork city. It places these trends in the context of both the British reprisal campaign in Cork city, and the IRA's guerrilla struggle. The book contains significant original research that focuses on events in Cork city in 1920-1921. Chapters on the British reprisal campaign, the IRA intelligence network, and the trends of the conflict provide unique evidence and conclusions regarding the situation in Cork city, which have not been published in any other work and directly contradicts some conclusions made in Peter Hart's The IRA and its Enemies.